Player-piano mechanism



1930- H. o. GRAU 1,772,249

PLAYER PIANO MECHANISM Filed April 5, 1926 4 Sheets-Sheet l INVENTOR.

A TTO Y.

' Aug. 5, 1930. H. o. ,GRAU

PLAYER PIANO MECHANISM Filed April 5, 1926 48 a Q a 5a6 H 2/ 23 \a7 4 200 Z l q 4.; a Ll 4 Sheets-Sheet 2 War ATTOR Aug; 3 .0. GRAU 1,772,249

PLAYER PIANO MECHANISM Filed April 5, 1926 4 Sheets-Sheet 3 INVENTOR.

flwm I A TTORNE Y.

Patented Au 5, 1930 UNITED STATES PATENT OFFICE Y HENRY 'ocr'ro GRAU,

CHEVIOT, OHIO PLAYER-PIANO MECHANISM Application filed April 5,

My invention relates to pneumatically operated mechanisms that function to actuate the hammers of a iano, chimes, Xylophone, or other musical instrument having a striking mechanism.

" former combination to provide 3.

Such striker actuating mechanism may also be used to 0 crate the sustaining mechanism, loud and so. .t mechanisms, and to operate the tone shading portion of the reproducing mechanism. The mechanism is adapted to be built into the case with the musical instrument. i

The principal object of my invention is to provide sturdy, durable and sensitive pneumatic means for actuating the hammers. To those ends my invention comprises novel means for directing the flow of air thru passages communicating with chambers having diaphragms, means for bleeding certain of said passages, and means for enclosing and for protecting said diaphragms.

Another object of my invention is to eliminate the bellows heretofore used for each note producing unit and instead of such self-contained actuating unit mechanism. In layer mechanisms now in use, the chamois, (id or other leather used in the bellows is ex osed' to dust and dirt and in contact with reely circulating air, so that it becomes hard and brittle, requiring renewal frequently and this involves great trouble and expense.

Another object of my invention is to provide a complete and separate striker unit assembly adapted to function to produce one note, which assembly may be removed from a com )letey assembled player action without disturbing any of the other units or their connections.

Another object of my invention is to provide a player piano action suitable for use in either a grand or upright piano.

Another object of my invention is to provide means for limiting the stroke of the striking rocker arm and means to compensate for wear of the felt.

Another object of my invention is to provide means for readil. replacin the bleeder tubes with those of di erent siz orifice.

Another object of my invention is to pro- 1926. Serial No. 99,864.

vide external air to the inte'rior'of the striker or actuating unit directly through the easing, thus shortening the path of its travel to the power side of the actuating diaphragm, reducing friction and therefore increasing the efliciency of the unit.

In the particular embodiment of my invention selected for illustration,

Figure 1, is a vertical section from front to back thru an upright player piano, showing the complete action in side elevation,

Fig. 2, an enlarged detail, is a side elevat on of one player striking unit and connections mounted on the main channel shown in cross section; the units internal mechanism chambers and passages being shown in dotted lines; and a portion of the tube leading to the tracker bar being broken away,

Fig. 3, an enlarged detail, is a front elevation, of four striking units, the contiguous passages shown in dotted lines, mounted on a piece of the main channel,

Fig. 4, anenlarged detail, is a side elevation of the block which forms the casing of the striking unit, with the internal chambers and passages shown in dotted lines,

F g. 5, is a top plan view of the same,

Fig. 6, is a cross section on the line 8- 8 of Fig. 4,

Fig. 7, is a cross section on the line 9-9 of Fig. 4, offset as indicated on 5 by line 99,

Fig. 8,, is a cross section on the line 1010 of Fig. 4, I

Fig. 9, an enlarged detail, is an elevation of the double valve for both intake and enhaust, with part of the stem broken away,

'Fig. 10, an enlarged detail, is an elevation of the plunger and guide valve, with part 0 of the stem broken away,

F s a top n e o Fi Fig. 12, is a side elevation ofthje bleed tube. with part broken away,

Fig. 13, 'a. detail is a top plan view of the m? sft. s ts-ibi e eit s h l-sh ped bleed, with part of the stem broken away,

Fig.15, is a top plan viow of the valve p uc b a k,

Fig. 16, is a vertical section on 18-18 of Fig. 15,

Fig. 17, a detail, is an adjustable stop for striking rocker arm to correct for wear of i the felt cushioning,

Fig. 18, is a top plan view of the block which forms the casing for plunger valve, with the passages shown in dotted lines, and

Fig. 19, is a vertical section on the line 2121 of Fig. 18.

Referring now to the drawings, C is the usual upright piano case within which is mounted the complete piano action B, and the player action consisting of an upper portion A and a lower portion D.

Each or each group of the harp strings b are adapted to be struck by a hammer 72 actuated by manually striking the keys 5 or through mechanical means constituting the player action hereinafter described.

The lower portion of the player action consists of foot power actuated bellows (Z and adapted to be operated by treadle (Z operatively secured to the lower end of the vacuum tube (0 The tube (Z is connected at its upper end to the main channels (Z (i placed the latter above the former and extending in a horizontal direction within the case sub? stantially parallel with the key-board.

Mounted upon and positioned across each of the main channels are an appropriate number for a. y given scale of striking units a. These units are identical in every particular eXc-eoting as to the length and shape of the striking rocker arm which is altered to adapt it for proper contact with certain of the hammers.

The main casing a has two connected chambers above and a below separated by a main power diaphragm (l of soft leather or other suitable material. Upon this diaphragm rests the button of a strike plunger (1*, while its stein extends upward vertically thru the strike plunger valve casing a ter minatin g outside the unit just below a cushion a of felt or buckskin on the underside of a stop a secured to the striking rocker arm (11 and adjustable with relation thereto by means of the screw a".

The strike plunger valve casing member a is secured to the main casing (Z1 by i leans of screws (r with a piece of buckskin or other suitable packing material a between said members to ensure sealing fit. A chamber a is formed in the top of the member a and this chamber is closed at the top by :1 diaphragm of leather or other suitable material a, to the under side of which is secured a strike plunger guide valve a provided with vertical holes a in which are vertically positioned guide pins (4 fixed in the bottom wall of the chamber a and (r is the leather packing for strike plunger guide valve a.

Screws a pass thru the elements a and a and secure the unit a to the main channel the line board (Z with leather or other suitable packing a between and (Z has air passage (Z closed at the bottom by packing cl and channel board (Z A supporting post a is secured to the member a by screws (4 and supports the striking rocker arm a pivoted to it by the bushcd pin a. The felt,.buckskin or otherwise cushioned end a of the striking rocker arm a is adapted to actuate a hammer 6 The movement of the arm (5 may be limited by the adjustable screw a and its check button a which has felt or other pad 60 The tracker bar T is connected by the tube 25 to an adjustable bleeder tube a, the other end of which enters the chamber a formed in the upper side of the pouch block a. The block a fits into a notched out portion on the under side of the main casing (4 secured in position by screws on" and its cl amber registers with a corresponding chamber a in the main casing c and is separated there from by the diaphragm a of leather or other suitable material.

in double valve whose lower button a lnu; a cushion a of leather or other suitable mate rial on its top surface l as a stem to the upper end of which is secured the disc valve a" with cushion (e on its under surface.

The bleed tube (4 connects the tracker bar tube 6 with the chamber (r The port a in bleed tube a connects with the passage (4 in the main casing a and this passage at connects with the chamber 0;. The chamber a is connected by the passage (0 with a vertical passage a leading from the chamber (Z and an oblique passage a connecting with. the chamber a 7 A cartridge shaped bleeder tube a closes the outer end of the passage (0 which leads to the chamber a. Passage of is connected by the vertical passage a with the horizontal passage a in the strike plunger valve casing member a which connects with the chamber a. Passage is connected by passage a with passages a, a and (1 which tern'iinate on the upper surface of casing member 0'" under leather (2/ of valve disc a".

The operation is as follows:

The music roll sheet passes the face of the tracker bar T. the perforations in the music sheet passes over the end of the duct in the tracker bar thru which the particular unit action is co trolled, the vacuum is broken, air rushes thru the duct in the tracker bar thru tube t. bleeder tube a into chamber a and this forces upward the diaphragm a and the button (1 carrying its stem and the valve (1" upwardly opening the passages (i a", (Z50 to atmosphere. The air rushes in downwardly thru these passages to the passage a horizontally thru said passage, and upzvi dly and downwardly thru a and horizoi tally i" a to chamber a and horito r w a r d o ver hen one of zonta'lly thru a to chamber a; the dial? phragm a is forced upwardly carrying-button a and its stem upwardly. The an admitted to chamber a balances pressures above and below the diaphragm c overcoming any opposing pressure differential on this diaphragnr and the action or the diaphragm of forces the top of the stem against the cushion a, and raises the striking rocker arm a causing its cushioned end a to contact with the piano action so that the hammer b" will strike the h arp string 1 Since the atmospheric pressure above the diaphragm a 1s equal to the prcssu re in chamber of below the diaphragmc after air is admitted to this latter chamber, the air in the chamber a is greater than atmospheric pressure and consequently raises the stem a and its attendant parts, causing the stem to push against the felt a and button a raising the striking rocker arm (11, As soon as this perforation in the n'nisic sheet has passed the duct in the tracker bar and the blank paper takes its place, then tendency to vacuum created thru the channel (Z again asserts itself and the diaphragm a falls, the air having been blceded off thru the opening a, passage a, passage a? and passage or, channel 03", t-ube d and bellows (Z caus ing a" to seat. At the same time vacuum is created in passages a, a a passage a, passage a, passages a and a and chamhers a and a"? the air having been bleeded elf thru a allowing striking rocker arm a to fall along with plunger a and its con-- nections upon the downward movement of diaphragms a and a. It will be understood that there is at all times maintained a partial vacuum in a while the piano player act-ion is in operation.

It can readilybe soon from the description that with very little labor and knowledge of" such mechanism, any of the striker units may be removed and replaced without the usual taking apart of other contiguous units or whole tiers of units, or their connections. This improvement not only embodies a pronounced decrease in cost of repairing and replacing parts but makes possible the carrying as a standard part the striker unit a duplicate of which may be procured and used to replace a defective one.

As the power diaphragms a are protected from dust and dirt and enclosed so that they are not continuously in free contact with the air, their effective life is very greatly increased, and much expense and trouble saved thereby.

I do not wish to be limited to the precise structure shown and described for many changes may be made in the mechanism without departing from the spirit of my invention, and I claim as within the scope of my invention all forms readable on the claims.

'Lclaim asmy invention and desire to secure by Letters Patent of the United States:

1. In combination Withan air line having pressure and relief sides; pneumatic actuating means for musical instruments comprising a casing, two openings in said casing, one for connecting said casing with the pressure side and another for connecting said casing with thereliet side of said airline, an unitary means for producing pressure for the entire musical instrument, a chamber within said casing, a main power diaphragm disposed substantially horizontally across said chamber, means for'admitting external air under said diaphragm to raise it whenever ,the vacuum in said air line is broken, a plunger adapted to rest upon said diaphragm and to be actuated by it and power transmitting means-outside said casingadapted to be ac'tuated by said plunger.

2. F or use in a player piano action having an unitary pressure producing mechanism, a

separate striker unit for each note, said unit comprising a casing having chambers directly connected with the main air channel and with the air conduit connected with the tracker bar, and having a main power diaphragm and a valve operating diaphragm both substantially horizontally disposed within said chambers formed'in said casing, conduitmeans within said casing for con necting thetracker bar conduit with said valve operating diaphragm chamber, said valve-controlling ports toexternal air, said ports, and conduit means-within said cas ing for connecting the main air channel with the main diaphragm chamber above said diaphragm for exhausting air therefrom, conduit means within said casing for connecting the valve diaphragm chamber above its dia phragm with the main air channel for exhausting air therefrom, conduit means for conveying external air from said ports to the power diaphragm chamber below said diaphragm to force said diaphragm upwardly, and means operated by said main diaphragm for actuating power transmitting means located outside of said casing. 2'

3. For use in connection with a player pianoaction having an air line with pressure and relief sides,unitary means for producing pressure, a main air channel on the pressure side of said air line and a tracker bar, a complete and separate striker unit foreac h note, each 'said'unit comprising a rigidcasing directly connected with the main air channel and the air conduit-connected the tracker bar, a chamber within said {us} ing, a main power diaphragm disposed sta'ntially horizontally acrom saidchamber, a plunger actuated by said mainfpower diaphragm, power transmitting means actuated by said plunger, a second chamber "wthin saidcasing, a diaphragm disposedsubstantially horizontally across said second chamber, a valve opened by'th'e raisin'gof said Hal second diaphragm, ports opening conduit-s within said casing to external air upon the raising of said valve, said conduits connecting said ports with the chamber under said main power diaphragm, conduits connecting the main air channel with the chamber above said main power diaphragm and also with the chamber above said valve operating diaphragm, means for connecting the tracker-bar air conduit with the chamber under said valve operating diaphragm so that a partial vacuum will constantly be maintained in the chambers above both said diaphragms.

Pneumatic actuating means for the mechanical player mechanism of a musical instrument having an unitary pressure producing mechanism, comprising a casing for a striker unit, an opening in said casing directly connected with the vacuum channel oi the player mechanism, another opening in said casing connected with the trackenbar of said player mechanism, an air port through the casing of said mechanism to admit external air directly thereinto, a *alve to control the admission of air into said casing through said port upon admission or" air to said casing thru said inlet connected with the tracker-bar, a plunger to transmit power from said unit to other parts of the player mechanism, means for actuating said plunger, air passages to connect said port with said actuating means, and connections from said vacuum opening to said valve-actuating and plunger-actuating means to facilitate an unbalancing of pressures therein when air is admitted thereto.

Pneumatic actuating means for the mechanical player mechanism of a musical instrument having an unitary pressure pro ducing mechanism, comprising a casing for a striker unit, an opening in said casing directly connected with the vacuum channel of the player mechanism, another opening in said casing connected with the tracker bar of said mechanism, an air port thru the easing of said mechanism to admit external air directly thereinto, a valve to control the admission of air into said casing thru said port, a chamber, a diaphragm in said chamber to actuate said valve upon admission 01" air to said chamber under said diaphragm thru said inlet connected with the tracker bar, a plunger to transmit power, a second chamher, a diaphragm in said second chamber for actuating said plunger, air passages to conneet said port with the chamber under said diaphragm, connections from said vacuum opening to the chambers above said diaphragms actuating said valve and plunger to facilitate an unbalancing of pressures in the chambers in which said diaphragms are mounted when air is admitted to said chambers on the opposite sides of said diaphragms and means for bleeding away the air from the pressure sides or" said diaphragms thru the vacuum opening of said casing.

6. In a striker unit for the mechanical player mechanism of a musical instrument haying an unitary pressure producing mechanism, the combination oi a casing for said unit, a plunger to operate the power transmitting means, a diaphragm to actuate said plunger, an air port thru tire casing of said. unit, a valvv to control the admission of air into said ca ng thru said port, and connections tron-i .id port to the underside of said diaphragm to supply air thereto to actuate it.

7. In combination with a musical instrument having striking mechanism, a gas line with pressure and relief sides, and a unit: v means for producing said pressure; separate actuating mechanisms for each note of said each oi said actuating mechal a ceii ipletely encased remo vp i 'd casing 'lor said a chamber within said casing, a 1 diaphragm disposed across said cnamom', 11199.? 101' ea sing said diaphragm by combined vacuum and gas ii are, a plunge actuated by said diaphragm and power transmitting means outsmd casing adapted to be actuated by aid plunger to operate the striking mechanisn'i for one note, a connection from each actuati. mechan sm to the pressure side oi? connecting said casing with the air conduit. a chamber within said casin a 11min power dianl 'agm disposed across said chamber, means or causing said diaphragm to be raised by combined vacuum and air pressure, a plunger actuated by said diaphragm and power transmitting ineans outside said casing adapted to be actuated by said plunger. I

S). in combination witl he player mechanism oi a player piano, including a tracker bar. an air line with pi ssure and relief sides. and an unitary means for producing pres sure tor the entire mechanism: actuating mechanism compr ing a rigid removable ca ii chamber \1 in said cas ng. a main power diaphragm disposc d across aid chamber, air chambers anc pissasz'es within said casing and means for controlling the flow oi air therethrough, so that air pressure will be applied below and vacuum created above said dia hragm to raise it, a plunger actuated by said diaphragm and power transmit llo ting means outside said casing adapted to be actuated by said plunger.

10. In combination with a player mechanism of a player piano, including a tracker bar, an air line with pressure and relief sides, and an unitary means for producing pressure for the entire mechanism; actuating means comprising a rigid removable casing, a connection from said casing to the pressure side of said air line, a connection from said casing to the relief side of said air line, a chamber formed within said casing, a main power diaph 'agm disposed substantially horizontally across said chamber, means within said casing for causing said main power diaphragm to be raised by combined vacuum above and air pressure below said diaphragm, a plunger actuated by said diaphragm, power transmitting means pivoted to the outside of said casing and adapted to be actuated by said plunger, and a second diaphragm above the first to which said plunger is secured, and means for supplying air pressure to the underside of said second diaphragm.

11. A player piano action having in combination, a tracker bar, an air conduit connected at one end to said tracker bar, a self contained note producing unit for each note connected to said air conduit and comprising, a rigid casing, a small air chamber con, nected to said air conduit, a main air chamber and a plurality of air passages within said casing, apertures through said easing into said air passages, a plunger valve normally closing said apertures and a flexible diaphragm in said small chamber actuating said plunger and valve, a striking rocker arm pivotally connected to said casing, a strike plungersecured to said arm and extending through said casing into said main air chamber, a diaphragm horizontally disposed across said chamber actuating said strike plunger, a single bellows for all said note producing units and air connectionsi from said bellows to said units.

12. In combination with the player action of a piano, an unitary self contained note producing means for each note, comprising a casing all the Walls of which are immovably fixed, a main air chamber and an auxiliary air chamber within said casing, interrelated air passages within said casing, apertures through said casing into said passages, a plunger valve normally closing said apertures, a diaphragm in said auxiliary chamber actuating said plunger valve, a striking rocker arm pivotally fixed to said casing, a strike plunger secured to said arm and extending through said casing into said main air chamber and a diaphragm in said main air chamber actuating said strike plunger.

In testimony whereof I have hereunto set my hand.

HENRY o'rro GRAU. 

